Subject: US: Cannabis Use and Cognitive Decline in Persons under 65 Years of Age



Pubdate: 1 May 1999



Source: American Journal of Epidemiology 1999; 149:794-800 



Authors: Constantine G. Lyketsos, Elizabeth Garrett, Kung-Yee Liang, and

James C. Anthony (Osler 320, The Johns Hopkins Hospital, 600 North Wolfe

Street, Baltimore, MD 21287-5371) 





CANNABIS USE AND COGNITIVE DECLINE IN PERSONS UNDER 65 YEARS OF AGE



The purpose of this study was to investigate possible adverse effects

of cannabis use on cognitive decline after 12 years in persons under

age 65 years.



This was a follow-up study of a probability sample of the adult

household residents of East Baltimore. The analyses included 1,318

participants in the Baltimore, Maryland, portion of the Epidemiologic

Catchment Area study who completed the Mini-Mental State (MMSE)

examination during three study waves in 1981, 1982, and 1993--1996.

Individual MMSE score differences between waves 2 and 3 were

calculated for each study participant. After 12 years, study

participants' scores declined a mean of 1.20 points on the MMSE

(standard deviation 1.90), with 66% having scores that declined by at

least one point.



Significant numbers of scores declined by three points or more (15% of

participants in the 18--29 age group). There were no significant

differences in cognitive decline between heavy users, light users, and

nonusers of cannabis.



There were also no male-female differences in cognitive decline in

relation to cannabis use. The authors conclude that over long time

periods, in persons under age 65 years, cognitive decline occurs in

all age groups. This decline is closely associated with aging and

educational level but does not appear to be associated with cannabis

use.